The invention relates to the alerting systems for maintaining the awareness of a vehicle's driver.
When the drive is fatigued from work, or operates his vehicle for extended time without rest, or the like--such a long monotonous drive can cause the driver to become inattentive to his driving. Failure of the driver to be alert and pay attention to proper operation of the vehicle is hazardous both to the driver and to other vehicles on the road. Nevertheless, in general, drivers don't realize their condition and tend to continue to drive their vehicles regardless of their ability to do it properly.
To prevent this a device has been proposed, U.S. Pat. No. 5,469,143 to Cooper (1995), which includes a pair of eyeglasses, comprising a micro-switch, coupled to a sensing lever, that is in constant contact with one of the driver's upper eyelid muscles, and electrically connected to a control unit. If the driver's eyelid fails to open at a predetermined time, the chain "sensing lever--micro-switch--control unit" produces an alarm signal.
Besides its complexity and inconvenience in use, this device is not reliable enough, because it is known that for some people open eyes do not mean that they are in an alert state.
One more safety device has been proposed, U.S. Pat. No. 3,409,101 to Williams (1968), which is implemented as a special foot pedal on the floor of the driver's compartment, which, upon depression, will activate an indicator switch for generating an alert signal, when the driver relaxes his pressure on the pedal, because he starts to drowse.
Besides the inconvenience of providing of not related to the driving process additional article to already crowded pedal area, said technical solution is not reliable enough, because it counts on a premise, that the drowsing driver will relax the pressure of his foot to the pedal, which is not quite true; the driver may be asleep and still apply the weight of his foot to the pedal.
Another device has been proposed in the U.S. Pat. No. 5,402,108 to Tabin (1995), wherein a signal for requesting a driver's response is provided in a time interval, and a decrease in driver's awareness is determined from a response time of the driver to the given signal.
The basic principle of "Alertness detecting and warning system for automobile" disclosed in U.S. Pat. No. 5,675,313 to Keluskar (1997) is, that the driver is required to use at least one of the pedals--either an accelerator, or brake, or special auxiliary pedal--during the predetermined time. Failure of the driver to do so initiates the warning system.
U.S. Pat. No. 4,234,051 to Moria discloses a driver alertness device, which includes a decrementing counter, that is resettable by the driver, a display to be observed by the driver, and a warning system. The driver must reset the decrementing counter before it reaches the predetermined time setting (between 0 and 10 minutes), as indicated by the display. Failure of the driver to do that results in activation of the warning system.
The verification of driver's awareness in apparatuses shown in U.S. Pat. No. 3,409,101, No. 5,402,108, No. 5,675,313, and No. 4,234,051 is based on his special actions in response to, or to avert the preliminary signals, which become additional to driver's common duties, distract him from operating his vehicle and make him more tired.
None of the above-mentioned solutions considers the fact, that a decrease of the level of the driver's awareness may occur (and does occur) at any time during the predetermined intervals between the preliminary signals. Thus, they admit, that for some indefinite time the vehicle may be operated by an inattentive driver, which undermines the whole idea behind this kind of devices.
A primary objective of the present invention is to provide an immediate activation of the warning/alarm system as soon as the driver's awareness starts to decrease, regardless of his recognition of that.